Electrical device

ABSTRACT

An electrical connector assembly includes an upper connector unit and a lower connector unit in a vertical direction. Each connector unit includes a contact module received within an insulative housing. The contact module includes an upper contact unit and a lower contacts unit stacked with each other. Each of the upper contact unit and the lower contact unit includes a front/outer contact part and a rear/inner contact part each including a plurality contacts essentially composed of a plurality of differential-pair signal contacts and a plurality of grounding contacts alternately arranged with each other in a the transverse direction wherein the differential-pair signal contacts are stamped and formed from sheet metal and successively integrally formed with a plurality of insulative transverse bars via insert-molding while the grounding contacts are directly blanked from sheet metal and associated with corresponding shielding plates assembled to the insulative transverse bar.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Application No. 63/090,225, filed Oct. 10, 2020, the content of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates generally to an electrical device having a metallic cage enclosing an electrical connector assembly wherein the electrical connector assembly includes an upper connector unit and a lower connector unit each having the corresponding contact module equipped with plural formed signal contacts and plural interstitial blanked grounding contact.

2. Description of Related Art

U.S. Pat. No. 10,461,475 discloses a QSFP-DD (Quad Small Form Factor Pluggable Double Density) dual port connector which is equipped with a plurality of transverse grounding bars to respectively mechanically and electrically connect to the corresponding grounding contacts for anti-EMI (Electromagnetic Interference). U.S. Provisional Application No. 63/053,611, filed Jul. 18, 2020, also discloses similar concept. Anyhow, to increase the EMI shielding effect, it is desired to provide a relatively large shielding plate between every adjacent to differential-pair signal contacts in the transverse direction. Anyhow, it is also preferred to have the signal contacts stamped and formed to be in an edge coupling manner for better SI (Signal Integrity) performance.

SUMMARY OF THE INVENTION

Therefore, the invention is to provide a hybrid contact arrangement in the connector wherein the signal contacts are stamped and formed while the grounding contacts are blanked and associated with the corresponding shielding plates to efficiently separate the neighboring differential-pair signal contacts. An electrical connector assembly includes an upper connector unit and a lower connector unit in a vertical direction. Each connector unit includes a contact module received within an insulative housing. The contact module includes an upper contact unit and a lower contacts unit stacked with each other. Each of the upper contact unit and the lower contact unit includes a front/outer contact part and a rear/inner contact part each including a plurality contacts essentially composed of a plurality of differential-pair signal contacts and a plurality of grounding contacts alternately arranged with each other in a the transverse direction wherein the differential-pair signal contacts are stamped and formed from sheet metal and successively integrally formed with a plurality of insulative transverse bars via insert-molding while the grounding contacts are directly blanked from sheet metal and associated with corresponding shielding plates assembled to the insulative transverse bar. Structurally, the grounding contacts of the front/outer contact part are unitarily paired with the corresponding grounding contacts of the rear/inner contact part, respectively, via the corresponding shielding plates. The housing forms opposite grooves to receive opposite ends of the insulative transverse bars so as to assemble the contact module within the housing.

Other advantages and novel features of the invention will become more apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an electrical device mounted upon a printed circuit board;

FIG. 2 is a perspective view of the electrical device mounted upon the printed circuit board of FIG. 1 without the metal cage;

FIG. 3 is a side view of the electrical device mounted upon the printed circuit board of FIG. 2;

FIG. 4 is an exploded perspective view of the electrical device on the printed circuit board of FIG. 1;

FIG. 5 is another exploded perspective view of the electrical device on the printed circuit board of FIG. 4;

FIG. 6 is a perspective view of a contact module of the electrical connector assembly of the electrical device on the printed circuit board of FIG. 4;

FIG. 7 is an enlarged perspective view of the contact module of the electrical connector assembly of the electrical device of FIG. 6;

FIG. 8(A) is a perspective view of the electrical connector assembly of the electrical device upon the printed circuit board of FIG. 1 wherein the upper connector unit is removed away from the lower connector unit;

FIG. 8(B) is another perspective view of the electrical connector assembly of the electrical device upon the printed circuit board of FIG. 8(A);

FIG. 9(A) is a perspective view of the upper connector unit of the electrical connector assembly of the electrical device of FIG. 8(A);

FIG. 9(B) is another perspective view of the upper connector unit of the electrical connector assembly of the electrical device of FIG. 9(A);

FIG. 10(A) is an exploded perspective view of the upper connector unit of the electrical connector assembly of the electrical device of FIG. 9(A);

FIG. 10(B) is another perspective view of the upper connector unit of the electrical connector assembly of the electrical device of FIG. 10(A);

FIG. 11(A) is a further exploded perspective view of the upper connector unit of the electrical connector assembly of the electrical device of FIG. 10(A);

FIG. 11(B) is another exploded perspective view of the upper connector unit of the electrical connector assembly of the electrical device of FIG. 10(A);

FIG. 12(A) is an exploded perspective view of the contact module of the upper connector unit of the electrical connector assembly of the electrical device of FIG. 11(A);

FIG. 12(B) is another perspective view of the contact module of the upper connector unit of the electrical connector assembly of the electrical device of FIG. 12(A);

FIG. 13(A) is an enlarged exploded perspective view of the lower contact unit of the contact module of the upper connector unit of the electrical connector assembly of the electrical device of FIG. 12(A);

FIG. 13(B) is an enlarged exploded perspective view of the upper contact unit of the contact module of the upper connector unit of the electrical connector assembly of the electrical device of FIG. 12(B);

FIG. 14 is a cross-sectional view of electrical device mounted upon the printed circuit board of FIG. 1;

FIG. 14(A) is an enlarged cross-sectional view of electrical device mounted upon the printed circuit board of FIG. 14(A);

FIG. 15(A) is a perspective view of the lower connector unit of the electrical connector assembly of electrical device of FIG. 8(A);

FIG. 15(B) is another perspective view of the lower connector unit of the electrical connector assembly of electrical device of FIG. 15(A);

FIG. 16(A) is an exploded perspective view of the lower connector unit of the electrical connector assembly of electrical device of FIG. 15(A); and

FIG. 16(B) is another perspective view of the lower connector unit of the electrical connector assembly of electrical device of FIG. 16(A).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to the embodiments of the present disclosure.

Referring to FIGS. 1-16(B), an electrical device 800 mounted upon a printed circuit board 900 to commonly form an electrical assembly 100. The electrical device 800 is essentially of a QSFP-DD interface, and includes an electrical connector assembly 110/210 surrounded by a metal cage which is composed of U-shaped main body 821, a bottom wall 822, a rear wall 823, and an outer grounding clip 824 located at a front end region of the main body 821 and equipped with a plurality of sprint tangs (not labeled) for contacting the external chase (not shown) which surrounds the metal cage, and the a pluggable QSFP-DD transceiver module (not shown) which is received within the metal cage and mechanically and electrically connects to the electrical assembly 100. A heat sink 810 is secured within the cage and essentially between the upper mating port 191 of the upper connector unit 110 and the lower mating port 221 of the lower connector unit 210. An inner grounding clip 825 surrounds a front end region of the heat sink 810 for mechanically and electrically connecting to the aforementioned pluggable QSFP-DD transceiver module.

The electrical connector assembly 110/210 includes a lower connector unit 210 and an upper connector unit 110 stacked upon the lower connector unit 110. The lower connector unit 210 includes an insulative lower housing 220 forming a lower mating port 221, a plurality of passageways 222 by two sides of the lower mating port 221, a plurality of opposite grooves 223 in two opposite side walls, and a rear space 225. Each side wall forms an assembling recess 224. A (lower) contact module 237 is composed of an upper contact unit 235 and a lower contact unit 236 wherein the upper contact unit 235 is composed of a front/outer contact part 231 and a rear/inner contact part 232, and the lower contact unit 236 is composed of a front-outer contact part 234 and a rear/inner contact part 233. The contact module 237 is assembled into the receiving space 235 by having two opposite ends of the corresponding insulative transverse bar (not labeled) of each part received within the corresponding grooves 223 A cap 240 is retained between opposite horizontal channels (not labeled) in the opposite side walls and above the contact module 237. Understandably, the contacting sections of the contacts of the contact module 237 are receiving within the passageways 222 and exposed in the lower mating port 221 for mating with the corresponding/inserted pluggable transceiver module (not shown).

The upper connector unit 110 includes an (upper) contact module 120 received within an insulative upper housing 190. The upper housing 190 forms an upper mating port 191 for receiving a pluggable transceiver module (not shown), and a plurality of passageways 192 by two sides of the upper mating port 191, a pair of alignment posts 193 for receipt within the corresponding recesses 224 of the lower housing 220 of the lower connector unit 210, a pair of (inner) grooves 195 in the opposite side walls (not labeled), and a rear space 194 for receiving the contact module 120.

The contact module 120 is composed of a lower contact unit 130 and an upper contact unit 160 stacked upon the lower contact unit 130. As shown in FIG. 13(A), the lower contact unit 130 includes a front/outer contact part 140, a rea/inner contact part 150, and a shielding plate part 132 sandwiched therebetween. The front/outer contact part 140 includes plural pairs of differential-pair signal contacts 142 side by side arranged with one another along the transverse direction, and integrally formed, via insert-molding, with an insulative front transverse bar 144 a, an insulative middle transverse bar 144 b and an insulative transverse bar 144 c. A plurality of slots 145 and a plurality of paired slots 146 are formed in the front transverse bar 144 a, a plurality of slots 147 are formed in the middle transverse bar 144 b, and a plurality slots 148 are formed in the rear transverse bar 144 c. The rear transverse bar 144 c further includes a plurality of protruding poles 144 cp on a rear side, and a pair of guiding protrusions 149 on two opposite sides. The differential-pair signal contacts 142 have corresponding contacting sections 141 in front of the front transverse bar 144 a for receipt within the corresponding passageways 192 to be exposed in the upper mating port 191 for mating with the pluggable transceiver module (not shown), and a plurality of solder tails 143 around the rear transverse bar 144 c for mounting to the printed circuit board 900.

Similarly, the rear/inner contact part 150 includes plural pairs of differential-pair signal contacts 152 side by side arranged with one another along the transverse direction, and integrally formed, via insert-molding, with an insulative front transverse bar 154 a, an insulative transverse bar 154 b and an insulative rear transverse bar 154 c. A plurality of slots 155 are formed in the front transverse bar 154 a, a plurality of slots 157 are formed in the middle transverse bar 154 b, and a plurality of slots 158 are formed in the rear transverse bar 154 c. The rear transverse bar 154 c further includes a pair of guiding protrusions 159 on two opposite sides, and a plurality of protruding poles 154 cp on the rear side. The differential-pair signal contacts 152 have contacting sections 151 in front of the front transverse bar 154 a for receipt within the corresponding passageways 192 to be exposed into the upper mating port 191 for mating with the pluggable transceiver module (not shown), and solder tails 153 around the rear transverse bar 154 c for mounting to the printed circuit board 900.

The shielding plate part 132 includes a plurality of metallic shielding plates 134 arranged with and spaced from one another along the transverse direction. Each is unitarily formed with a front/outer grounding contact 133 a and a rear/inner grounding contact 133 b, a forward lance 136 and a rearward lance 135, and a front solder tail 135 a and a rear solder tail 135 b. In other words, each shielding plate 134 functions as two grounding contacts unified together.

When assembled, the front lances 136 are inserted into the corresponding slots 147 of the front/outer contact part 140, and the rear lances 135 are inserted into the corresponding slots 157 of the rear/inner contact part 150 as so to have the whole lower contact unit 130 is secured. The front solder tails 135 a are received within the corresponding slots 148, and the rear solder tails 135 b are received within the corresponding slots 158. Specifically, the front transverse bar 154 a of the rear/inner contact part 150 is essentially located between the front/outer grounding contacts 133 a and the rear/inner grounding contacts 133 b. The front/outer grounding contacts 133 a extend through the corresponding slots 145 of the front/outer contact part 140, the rear/inner grounding contacts 1336 extend through the corresponding slot 155 of the rear/inner contact part 150 and are movable within the corresponding slots 145 of the front/outer contact part 140 upon downward deflection by the inserted pluggable transceiver module (not shown). Similarly, the contacting sections 151 of the rear/inner contact part 150 are moveable within the corresponding slots 146 of the front/outer contact part 140 upon downward deflection by the inserted pluggable transceiver module (not shown). The protruding poles 144 cp of the front/outer contact part 140 are received within the corresponding holes (not shown) in the rear transverse bar 154 c of the rear/inner contact part 150 so as to have the rear transverse bar 144 c of the front/outer contact part 140 and the rear transverse bar 154 c of the rear/inner contact part 150 are intimately assembled with each other. The guiding protrusions 149 of the front/outer contact part 140 and the guiding protrusions 159 of the rear/inner contact part 150 are commonly received within the corresponding grooves 195 of the upper housing 190. Understandably, the housing 190 also includes corresponding grooves (not shown) to receive the opposite ends of the front transverse bar 144 a. Notably, in the transverse direction the front/outer grounding contacts 133 a are aligned with the contacting sections 141 of the front/outer contact part 140, and rear/inner grounding contacts 133 b are aligned with the contacting sections 151 of the rear/inner contact part 150. As well, the solder tails 135 a are aligned with the solder tails 143, and the solder tails 135 b are aligned with the solder tails 153 in the transverse direction. Understandably, compared with the traditional respective grounding contacts, the shielding plates 134 provides enlarged shielding area in the transverse direction so as to enhance of the shielding effect between the neighboring differential-pair signal contacts 142/152.

Similar to the arrangement of the lower contact unit 130 disclosed in FIG. 13(A), the upper contact unit 160 as shown in FIG. 13(B) includes a front/outer contact part 170, a rear/inner contact part 180, and a shielding plate part 162 sandwiched therebetween. The front/outer contact part 170 includes plural pairs of differential-pair signal contacts 172 integrally formed with the front transverse bar 174 a, the middle transverse bar 174 b, and a rear transverse bar 174 c. The slots 175, 177 and 178 are respectively formed in the front transverse bar 174 a, the middle transverse bar 174 b and the rear transverse bar 174 c. The rear transverse bar 174 c further includes the protruding poles 174 cp and the guiding protrusions 179. The differential-pair signal contacts 172 have corresponding contacting sections 171 and solder tails 173. The rear/inner contact part 180 includes plural pairs of differential-pair signal contacts 182 integrally formed with the front transverse bar 184 a, the middle transverse bar 184 b and the rear transverse bar 184 c. The slots 185, 187 and 188 are formed in the front transverse bar 184 a, the middle transverse bar 184 b and the rear transverse bar 184 c, respectively. The rear transverse bar 184 c further includes protruding poles 184 cp and guiding protrusions 189. The differential-pair signal contacts 182 have corresponding contacting sections 181 and solder tails 183. The shielding plate part 162 includes a plurality of shielding plates 164. Each shielding plat 164 includes a front/outer grounding contact 163 a and a rear/inner grounding contact 163 b around a front area, a pair of lances 165 and 166 around the middle area, and a pair of solder tails 165 a and 165 b around the rear area. Notably, because the arrangement of the upper contact unit 160 is similar to that of the lower contact unit 130, no detailed description is required. In addition, the protruding poles 154 cp are received within the corresponding holes (not shown) in the transverse bar 184 c as shown in FIG. 14(A).

In brief, the invention is to provide the hybrid type contact arrangement in the connector wherein the front grounding contact is unitarily, in a blanked manner, formed with the rear grounding contact via an enlarged shielding plate so as to provide better shielding effect between the neighboring differential-pair signal contacts in the transverse direction while still allowing the differential-pair signal contacts to be formed in a relatively deformable manner compared with the blanked manner, advantageously. Although the present invention has been described with reference to particular embodiments, it is not to be construed as being limited thereto. Various alterations and modifications can be made to the embodiments without in any way departing from the scope or spirit of the present invention as defined in the appended claims.

Although the present invention has been described with reference to particular embodiments, it is not to be construed as being limited thereto. Various alterations and modifications can be made to the embodiments without in any way departing from the scope or spirit of the present invention as defined in the appended claims. 

What is claimed is:
 1. An electrical connector comprising: an insulative housing defining a front mating slot for receiving a mating plug along a front to rear direction; and a contact module receiving in the insulative housing and comprising: a first contact part comprising a pair of first differential signal contacts and a first insulative bar fixed with the first pair of differential signal contacts, each of the first differential signal contacts comprising a first signal mating portion, a first signal mounting portion for being mounting to an outer printed circuit board, and a first signal body portion connected therebetween; a second contact part comprising a pair of second differential signal contacts and a second insulative bar fixed with the pair of second differential signal contacts, each of the second differential signal contacts comprising a second signal mating portion, a second signal mounting portion for being mounting to the outer printed circuit board, and a second signal body portion connected therebetween; and a shielding member fixed with the first insulative bar and comprising a first grounding mating portion disposed adjacent to and aligned with the pair of first signal mating portions, a first grounding tail disposed adjacent to and aligned with the pair of first signal mating portions, and a grounding body portion extending therebetween.
 2. The electrical connector as claimed in claim 1, wherein the second signal mating portions and the first signal mating portions are disposed at a same side of the front mating slot, the second signal mating portions disposed at a rear side of the first signal mating portions, the second signal mounting portions disposed at a rear side of the first signal mounting portions.
 3. The electrical connector as claimed in claim 2, wherein the shielding member is fixed with the second insulative bar, the shielding member comprising a second grounding mating portion disposed adjacent to and aligned with the pair of the second signal mating portions and a second grounding tail disposed adjacent to and aligned with the pair of the second signal mating portions.
 4. The electrical connector as claimed in claim 3, wherein the grounding portion having a width measured along the front to rear direction is equal to or larger than a width measured from a front side of the first pair of differential signal contacts to a rear side of the second pair of differential signal contacts along the front to rear direction.
 5. The electrical connector as claimed in claim 3, wherein the first grounding mating portion, the second grounding mating portion, the grounding body portion, the first grounding tail and the second grounding tail are disposed at a same plane.
 6. The electrical connector as claimed in claim 3, wherein the first contact part comprises a first front insulative bar defining a plurality of slots for receiving the second signal mating portions and the second grounding mating portion, respectively.
 7. The electrical connector as claimed in claim 3, wherein the shielding member comprises a first lances extending forwardly to fix with the first insulative bar, and a second lances extending rearwardly to fix with the second insulative bar.
 8. The electrical connector as claimed in claim 1, wherein the first contact part comprises a first rear insulative bar, and the second contact part comprises a second rear insulative bar mated with the first rear insulative bar.
 9. The electrical connector as claimed in claim 8, wherein the first rear insulative bar defines a slot receiving a front portion of the grounding body portion, and the second rear insulative bar defines a slot receiving a rear portion of the grounding body portion.
 10. The electrical connector as claimed in claim 2, wherein the contact module comprises: a third contact part comprising a pair of third differential signal contacts and a third insulative bar fixed with the third pair of differential signal contacts, both of the third differential signal contacts comprising a third signal mating portion opposite to the first signal mating portion, a third signal mounting portion disposed at rear side of the second signal mounting portion for being mounting to the outer printed circuit board, and a third signal body portion connected therebetween; a fourth contact part comprising a pair of fourth differential signal contacts and a fourth insulative bar fixed with the fourth pair of differential signal contacts, both of the fourth differential signal contacts comprising a fourth signal mating portion opposite to the second signal mating portion, a fourth signal mounting portion disposed between the second signal mounting portion and the third signal mounting portion for being mounting to the outer printed circuit board, and a fourth signal body portion connected therebetween; and a shielding member fixed with the third insulative bar, comprising a third grounding mating portion disposed adjacent to and aligned with the pair of the third signal mating portions, a fourth grounding mating portion disposed adjacent to and aligned with the pair of the fourth signal mating portions, a third grounding tail disposed adjacent to and aligned with the pair of the third signal mating portions, a fourth grounding tail disposed adjacent to and aligned with the pair of the fourth signal mating portions, and a grounding body portion extending therebetween.
 11. The electrical connector as claimed in claim 10, wherein the grounding portion having a width measured along the front to rear direction is equal to or larger than a width measured from a front side of the fourth pair of differential signal contacts to a rear side of the third pair of differential signal contacts along the front to rear direction.
 12. An electrical connector comprising: an insulative housing; a first contact module receiving in the insulative housing comprising: a first contact part comprising a plurality of first differential-pair signal contacts and a first insulative bar molded with the first differential-pair signal contacts, each of the first differential-pair signal contacts comprising a first signal mating portion; a second contact part comprising a plurality of second differential-pair signal contacts and a second insulative bar molded with the second differential-pair signal contacts, each of the second differential-pair signal contacts comprising a second signal mating portion; and a first shielding member connected with the first insulative bar and the second insulative bar, the first shielding member comprising a first grounding mating portion disposed between two adjacent first differential-pair signal contacts and aligned with the first signal mating portion, a second grounding mating portion disposed between two adjacent second differential-pair signal contacts and aligned with the second signal mating portion; and a second contact module receiving in the insulative housing comprising: a third contact part comprising a plurality of third differential-pair signal contacts and a third insulative bar molded with the third differential-pair signal contacts, each of the third differential-pair signal contacts comprising a third signal mating portion opposite to the first signal mating portion; a fourth contact part comprising a plurality of fourth differential-pair signal contacts and a fourth insulative bar molded with the fourth differential-pair signal contacts, each of the fourth differential-pair signal contacts comprising a fourth signal mating portion opposite to the second signal mating portion; and a second shielding member connected with the third insulative bar and the fourth insulative bar, the second shielding member comprising a third grounding mating portion disposed between two adjacent third differential-pair signal contacts and aligned with the third signal mating portion, a fourth grounding mating portion disposed between two adjacent fourth differential-pair signal contacts and aligned with the fourth signal mating portion.
 13. The electrical connector as claimed in claim 12, wherein each first differential-pair signal contact comprises a first signal tail, and a first signal body portion connected between the first signal tail and the first signal mating portion, each second differential-pair signal contact comprising a second signal tail disposed at a rear of the first signal tail, and a second signal body portion connected between the second signal tail and the second signal mating portion, each third differential-pair signal contact comprising a third signal tail disposed at a rear of the second signal tail, and a third signal body portion connected between the third signal tail and the third signal mating portion, each fourth differential-pair signal contact comprising a fourth signal tail disposed between the second signal tail and the third signal tail, and a fourth signal body portion connected between the fourth signal tail and the fourth signal mating portion.
 14. The electrical connector as claimed in claim 13, wherein the first shielding member comprises a first grounding tail aligned with the first signal tails, a second grounding tail aligned with the second signal tails, and a first grounding body portion connected between the first grounding mating portion, the second grounding mating portion, and the first grounding tail, the second grounding tail, the second shielding member comprises a third grounding tail aligned with the third signal tails, a fourth grounding tail aligned with the fourth signal tails, and a second grounding body portion connected between the third grounding mating portion, the fourth grounding mating portion, and the third grounding tail, the fourth grounding tail.
 15. The electrical connector as claimed in claim 12, wherein the first grounding mating portion and the second grounding mating portion are in same vertical plane and spaced apart from each other along a front to rear direction; and the third grounding mating portion and the fourth grounding mating portion are in another same vertical plane and spaced apart from each other along the front to rear direction.
 16. The electrical connector as claimed in claim 12, wherein the first contact part comprises a first rear insulative bar, the second contact part comprising a second rear insulative bar mated with the first rear insulative bar, the fourth contact part comprising a fourth rear insulative bar mated with the second rear insulative bar, the third contact part comprising a third rear insulative bar mated with the fourth rear insulative bar.
 17. The electrical connector as claimed in claim 12, wherein the insulative housing defines a mating slot for receiving a plug and a receiving space below the mating slot for receiving a lower connector unit defining a mating slot for receiving another plug.
 18. An electrical connector comprising: an insulative housing defining a rear receiving space and a front mating port; and a contact module received within the receiving space and comprising an upper contact unit and a lower contact unit, each of the upper contact unit and the lower contact unit comprising: a front/outer contact part, a rear/inner contact part, and a shielding plate part sandwiched therebetween, the front/outer contact part including plural pairs of differential-pair signal contacts integrally formed with an insulative transverse bar via insert-molding, the rear/inner contact part including plural pairs of differential-pair signal contacts integrally formed with another insulative transverse bar via insert-molding, and the shielding plate part includes a plurality of metallic shielding plates each extending in a vertical plane perpendicular to a transverse direction and unitarily having a front grounding contact and a rear grounding contact around a front area thereof; wherein in the front mating port and along the transverse direction, the front grounding contacts are aligned with contacting sections of the differential-pairsignal contacts of the front/outer contact part and the rear grounding contacts are aligned with contacting sections of the differential-pair signal contacts of the rear/inner contact part.
 19. The electrical connector as claimed in claim 18, wherein the upper contact unit is mated with the lower contact unit.
 20. The electrical connector as claimed in claim 18, wherein the plurality of metallic shielding plates are arranged in plurality of vertical planes respectively, and the differential-pair signal contacts arranged in plurality of planes perpendicular to the vertical planes. 